Eluent for radioisotopes

ABSTRACT

This disclosure relates to an eluent which improves the yield of nuclear radioisotopes from ion exchange resins. The disclosure in essence concerns itself with the addition of an oxidizing agent to an isotonic saline solution, said oxidizing agent being present in a concentration of from about 0.001 percent to about 1.0 percent on a volume/volume ratio.

United States Patent Haney et a1.

451 May23, 1972 ELUENT FOR RADIOISOTOPES lnventors: Thomas A. Haney,East Brunswick; Gerald A. Bruno, Shrewsbury, both of NJ.

Assignee: E. R. Squibb & Sons, Inc., New York,

Filed: July 3, 1968 Appl. No.: 742,128

U.S. Cl ..252/364, 23/338, 210/31, 252/301.1 R

Int. Cl. ..B0lf l/00, C22b 61/04 Field of Search ..252/364, 95; 23/50BE, 338; 210/31 C References Cited UNlTED STATES PATENTS 2,780,5142/1957 Lutz ..23/338 3,002,823 10/1961 Flodin et al.. ...2l0/3l X3,393,153 7/1968 Zimmerer et al. ..252/95 Primary ExaminerRichard D.Lovering Attorney-Lawrence S. Levinson and Merle J. Smith [57] ABSTRACT4 Claims, No Drawings ELUENT FOR RADIOISOTOPES In recent yearsradioactive isotopes such as lodine Technetium 99", Yttrium, and manyothers, such as l-131, ST-85, Sr--87" and P-32, have been used in themedical and biological fields as tracer elements for investigative anddiagnostic purposes and in some cases as a therapeutic agent. Many ofthese radioactive isotopes are delivered to the user by means of agenerator, wherein the radioactive isotope is contained on an ionexchange resin in its parent form. By utilizing the proper eluent one isable to separate the daughter isotope from the parent which is adsorbedon an ion exchange resin. The generator thus utilized has become knownto the art as a cow and the operation of eluting the daughter isotopefrom its parent has become known as a milking" process.

Recently, new sterile generators which are sterile and nonpyrogenic havebeen developed and are presently on the market. The milking of thesegenerators is different in that hypodermic needles and syringes must beutilized and a sterile condition maintained throughout the operation.However, the present invention relates to both non-sterile and sterilegenerators.

It has been discovered that by the addition of an oxidizing agent to aneluent solution, the yield of the daughter isotope is significantlyincreased.

The eluent in this invention is a saline solution which is prepared bymethods known to the art. The saline solution may be 0.9 percent sodiumchloride solution or an isotonic sodium chloride solution. The oxidizingagent added to this solution may be oxygen (bubbling it through thesolution), an alkali metal hypochlorite (e.g., sodium hypochlorite), analkali metal permanganate (e.g., potassium permanganate), fertheradioisotope to be separated or eluted from the generator. The method ofutilizing the modified eluent of this invention is the same ascustomarily utilized in eluting generators whether they be of thesterile of non-sterile type.

The following examples illustrate the utilization of the eluent in theseparation of various radioisotopes. In these examples all degrees arein Centigrade, unless otherwise stated:

EXAMPLES 1 TO 20 The following solutions are prepared by proceduresknown to the art, except as otherwise stated:

Solution A Normal isotonic saline with parabens.

Solution B 0.9% Sodium chloride solution.

Solution C 0.9% Sodium chloride solution with 0.5%

available chlorine pH 5.3.

Solution D 0.9% Sodium chloride solution with 0.5%

available chlorine pH 4.5.

Solution E 0.9% Sodium chloride with 0.01% available chlorine H 5.5.Solutions C, and E which are isotonic chlorine saline solu- TABLE 1 [Tcyield using various eluting solutions] Generator MC Milking 'Ic T0 oPotency eluent MC /25 percent MO Gen. Milking assayed label solution ml.of label content 128 100 B 105 105 N one. 2 100 78 B 72 92 Do. 1001110..-- 78 61 B 52 85 Do. 4 61 47 D0. 47 37 E 34. 2 92 D0. is 316 200 B130 65 Do. 2 246 156 B 70 Do. 200 mc 192 122 B 47 39 Do. 4 150 95 Do.117 74 E )5 128 Do. 560 421 A 365 87 Do. 2d 266 200 A 11 5. 5 D0. 200me, 2d (i'e milk) 266 200 C 165 83 Do. 3d 207 156 A 170 10!] Do. 162 122A 110 00 D0. 790 632 A 416 66 Do. 375 300 A 13 4. 3 D0. 300 m(. 293 234A 23 10 D0. 4 h 288 183 A 21 11.5 D0. 4th (re milk) 288 183 D 110 60 Do.

ric chloride, hydrogen peroxide and an alkali metal perhalogenate (e.g.,potassium perchloride, sodium perbromide, and so forth). It is to beunderstood that both organic and inorganic oxidizing agents, such asperacetic acids, cupric acetate, iodoisobenzene, phenanthrenequinone,and pyridine N-oxide may also be utilized in the practice of thisinvention.

It has been found that a pH of the eluent of from about 3.0 to about 7.0is effective. However, superior results were obtained when the eluentwas maintained at a pH of from about 4 to about 6.8 with the bestresults being observed when the pH of the eluate was from about 5 toabout 6.5.

The concentration of the oxidizing agent on a v/v basis should be in therange of from about 0.01 percent to 0.1 percent. However, depending uponthe oxidizing agent utilized, a concentration in the range of from about0.001 percent to about 1 percent may be preferable. However, it has beendiscovered that extremely satisfactory results are obtained when theconcentration of the oxidizing agent is in the range on a v/v basis offrom about 0.02 percent to about 0.05 percent.

As indicated above the initial eluent may be sterilized water,sterilized saline solution, an acid eluent or basic eluent dependingupon the ion exchange resin utilized in the cow and From the above Tableit is established that the yield of Technetium 99" can be significantlyincreased by utilizing isotonic chlorine water.

The invention may be variously otherwise embodied within the scope ofthe appended claims.

What is claimed is:

1. An eluent solution for use in eluting radioactive isotopes from anion exchange resin consisting essentially of an isotonic saline solutionand an oxidizing agent said oxidizing agent being present in aconcentration of from about 0.001 percent to about 1.0 percent on avolume/volume ratio.

2. An eluent in accordance with claim 1 wherein the oxidizing agent isselected from the group consisting of oxygen, an alkali metalhypochlorite, an alkali metal permanganate, an alkali metalperhalogenate, ferric chloride, hydrogen peroxide, peracetic acids,cupric acetate, iodoisobenzene, phenanthrene-quinone and pyridineN-oxide.

3. An eluent in accordance with claim 1 wherein the pH of the eluent isfrom about 3.0 to about 7.0.

4. An eluent in accordance with claim 1 wherein the oxidizing agent ispresent in a concentration of from about 0.01 percent to 0. 1 percent ona volume/volume ratio.

2. An eluent in accordance with claim 1 wherein the oxidizing agent isselected from the group consisting of oxygen, an alkali metalhypochlorite, an alkali metal permanganate, an alkali metalperhalogenate, ferric chloride, hydrogen peroxide, peracetic acids,cupric acetate, iodoisobenzene, phenanthrene-quinone and pyridineN-oxide.
 3. An eluent in accordance with claim 1 wherein the pH of theeluent is from about 3.0 to about 7.0.
 4. An eluent in accordance withclaim 1 wherein the oxidizing agent is present in a concentration offrom about 0.01 percent to 0.1 percent on a volume/volume ratio.